hwc: Avoid fd leak on external rotator usecase.

When rotator is used for downscaling on external display,
- do not overwrite the releaseFenceFd if it is already
populated to avoid fd leak.
- do not reset the releasefencefd for RGB buffers.
- add error logging for rotator ioctl buffer sync.

CRs-Fixed: 505153
Change-Id: I78f3ba93676b6179932bf9c67d136b6eafc58aa9
Merge "hwc: Avoid fd leak on external rotator usecase."